Acyanotic congenital heart defects

1. E R I C M D 4
ACYANOTIC CONGENITAL
HEART DEFECTS

2. Atrial Septal Defect
Atrial septal defect (ASD) account for as an isolated
anomaly 5-10% of all CHD. Based on anatomy, ASD is
classified as follows:
Fossa ova/is ASD. They are located in the central portion
of atrial septum, in the position of foramen ovale. These
defects are amenable to closure in the catheterization
laboratory.
Sinus venosus ASD. These are located at junction of superior
vena cava and right atrium. These defects do not have a
superior margin because the superior vena cava straddles
the defect. These defects are associated with anomalous
drainage of one or more right pulmonary veins.

3. Ostium primum ASD. These defects are created by
failure
of septum primum, and are in lower part of the atrial
septum; inferior margin of ASD is formed by the
atrioventricular valve.
Coronary sinus ASD. An unroofed coronary sinus is a
rare
communication between the coronary sinus and the
left
atrium, which produces features similar to other types
of
ASD.

5. Physiology and Findings
The physiology of ASD is that of a pre-tricuspid shunt.
The enlarged right ventricle results in a parasternal
impulse. The ejection systolic murmur originates from the
pulmonary valve because of the increased blood flow. An
increased flow through the tricuspid valve may result in
a soft delayed diastolic rumble at the lower left sternal
border. The overload of the right ventricle due to an
increase in venous return prolongs the time required for
its emptying resulting in delayed P2.

6. This delay also
results from the prolonged 'hang-out' interval because of
the very low resistance in the pulmonary circulation.
Additionally, since the two atria being linked via the large
ASD, inspiration does not produce any net pressure
change between them and respiration related fluctuations
in systemic venous return to the right side of the heart are
abolished; thereby the fixed S2

7. The electrocardiogram of ostium secundum ASD is
characterized by right axis deviation and right
ventricular
hypertrophy. The chest X-ray shows mild to moderate
cardiomegaly, right atrial and right ventricular
enlargement, prominent main pulmonary artery
segment,
a relatively small aortic shadow and plethoric lung
fields. The left atrium does not enlarge in size in
atrial septal
defect, unless associated with other anomalies like
mitralregurgitation.

8. Natural History and Complications
Heart failure is exceptional in infancy. A small
proportion
of patients might develop pulmonary hypertension, by
the second or third decade. ASD closure is
recommended
to prevent complications of atrial arrhythmias and
heart
failure in late adulthood.

9. Treatment
Most fossa ovalis defects with good margins can be
closed
percutaneously in the catheterization laboratory with
occlusive devices. Others require surgical closure.
Closure
is recommended before school entry to prevent late
complications. Small defects ( <8 mm) can be
observed.
Spontaneous closure is well recognized in small defects
that are diagnosed in infancy or early childhood .

10. Ventricular Septal Defect (VSD)
This is the most common congenital cardiac lesion
identified at birth accounting for one-quarter of all
CHD.
VSD is a communication between the two ventricles;
90%
are located in the membranous part of the ventricular
septum with variable extension into the muscular
septum.
Others are located in the muscular septum and can be
multiple

11. Hemodynamics
VSD results in shunting of oxygenated blood from the left
to the right ventricle. The left ventricle starts
contractingbefore the right ventricle. The flow of blood
from the left
ventricle to the right ventricle starts early in systole. When
the defect is restrictive, a high pressure gradient is
maintained
between the two ventricles throughout the systole.
The murmur, starts early, masking the first sound and
continues throughout the systole with almost the same
intensity appearing as a pansystolic murmur on
auscultation
and palpable as a thrill.

12. Toward the end of systole,
the declining left ventricular pressure becomes lower than
the aortic pressure. This results in closure of the aortic
valve and occurrence of A2. At this time, however, the
left ventricular pressure is still higher than the right
ventricular pressure and the left to right shunt continues.
The left to right ventricular shunt occurs during systole
at a time when the right ventricle is also contracting and
its volume is decreasing. The left to right shunt, therefore,
streams to the pulmonary artery more or less directly. This
flow of blood across the normal pulmonary valve results
in an ejection systolic murmur at the pulmonary valve.

13. The large volume of blood passing through the lungs is
recognized in the chest X-ray as pulmonary plethora.
The
increased volume of blood finally reaches the left
atrium
and may result in left atrial enlargement. Passing
through a
normal mitral valve the large volume of blood results
in a
delayed diastolic murmur at the apex.

14. Clinical FeaturesPatients with VSD can become
symptomatic around 6 to
10 weeks of age with congestive cardiac failure. Premature
babies with a VSD can become symptomatic even earlier.
Palpitation, dyspnea on exertion and frequent chest
infection are the main symptoms in older children. The
precordium is hyperkinetic with a systolic thrill at the left
sternal border. The heart size is moderately enlarged with
a left ventricular type of apex. The first and the second
sounds
are masked by a pansystolic murmur at the left sternal
border.

15. The second sound can, however, be made out at the second
left interspace or higher. It is widely split and variable with
accentuated P2. A third sound may be audible at the apex.
A
loud pansystolic murmur is present at the left sternal
border.
The maximum intensity of the murmur may be in the third,
fourth or the fifth left interspace. It is well heard at the
second
left interspace but not conducted beyond the apex. A
delayed
diastolic murmur, starting with the third sound is audible
at the apex

16. The electrocardiogram in VSD is variable. Initially all
patients with VSD have right ventricular hypertrophy.
Because of the delay in the fall of pulmonary vascular
resistance due to the presence of VSD, the regression of
pulmonary arterial hypertension is delayed and right
ventricular hypertrophy regresses more slowly. In small
or medium sized VSD, the electrocardiogram becomes
normal. In patients with VSD and a large left to right
shunt,
without pulmonary arterial hypertension, the
electrocardiogram shows left ventricular hypertrophy by
the time they are six months to a year old.

17. Patients of VSD who have either
pulmonic stenosis or pulmonary arterial hypertension
may show right as well as left ventricular hypertrophy or
pure right ventricular hypertrophy. The cardiac silhouette
on chest X-ray is left ventricular
type with the heart size determined by the size of the left
to right shunt. The pulmonary vasculature is
increased; aorta appears normal or smaller than normal
in size. Echocardiogram shows increased left atrial and
ventricular size as well as exaggerated mitral valve motion.

18. Chest X-ray in ventricular septa! defect. Note the cardiac
enlargement mainly involving the left ventricle together with increased
lung vasculature as suggested by the size and increased number of
end-on vessels in the lung fields

19. Course and Complications
Patients with VSD have a very variable course. They may
develop congestive cardiac failure in infancy which is
potentially life threatening. It has been estimated that
almost 70% of all ventricular defects become smaller in
size. A smaller proportion will disappear entirely. In
almost 90% of patients who have spontaneous closure of
the defect, it occurs by the age of three years, though it
may occur as late as 25 yr or more.

20. Patients born with an uncomplicated VSD may
develop
p ulmonic stenosis due to hypertrophy of the right
ventricular infundibulum, develop pulmonary arterial
hypertension or rarely develop aortic regurgitation
due to
prolapse of the right coronary or the non-coronary
cusp
of the aortic valve.

21. Treatment
Medical management consists in control of congestive
cardiac failure, treatment of repeated chest infections
and
prevention and treatment of anemia and infective
endocarditis. The patients should be followed carefully
to assess the development of pulmonic stenosis,
pulmonary arterial hypertension or aortic
regurgitation.

22. Surgical treatment is indicated if: (i) congestive cardiac
failure occurs in infancy; (ii) the left to right shunt is large
(pulmonary flow more than twice the systemic flow); and
(iii) if there is associated pulmonic stenosis, pulmonary
arterial hypertension or aortic regurgitation. Surgical
treatment is not indicated in patients with a small VSD
and in those patients who have developed
severepulmonary arterial hypertension and significant
right to
left shunt

23. Operative treatment consists in closure of VSD with the
use
of a patch. The operation is performed through the right
atrium. The operation can be done as early as a few months
after birth if congestive failure cannot be controlled with
medical management. With evidence of pulmonary
hypertension, the operation should be performed as early
as possible

24. Hemodynamics and Clinical FeaturesPDA results in a left
to right shunt from the aorta to the
pulmonary artery. The flow occurs both during systole and
diastole as a pressure gradient is present throughout the
cardiac
cycle between the two great arteries, if the pulmonary
artery
pressure is normal. The flow of blood results in a murmur
that starts in systole, after the first sound, and reaches a
peak at the second sound. The murmur then diminishes
in intensity and is audible during only a part of the
diastole. Thus, it is a continuous murmur

25. The PDA results in a systolic as well as diastolic
overloading of the pulmonary artery. The increased flow
after passing through the lungs reaches the left atrium.
To accommodate the flow the left atrium enlarges in size.
The increased volume of blood reaching the left atrium
enters the left ventricle in diastole, across a normal mitral
valve. The passage of this increased flow across the mitral
valve results in an accentuated first sound as well as a
mitral delayed diastolic murmur

26. Patients with PDA may become symptomatic in early
life and develop congestive cardiac failure around 6-10
weeks of age. Older children give history of effort
intolerance, palpitation and frequent chest infections. The
flow from the aorta to the pulmonary artery is a leak from
the systemic flow. This results in a wide pulse pressure and
many of the signs of wide pulse pressure enumerated
earlier
in association with aortic regurgitation are present in
patients who have a PDA.

27. On the bedside, presence of
prominent carotid pulsations in a patient with features of
a left to right shunt suggests the presence of PDA. The
cardiac impulse is hyper kinetic with a left ventricular type
of apex. A systolic or a continuous thrill may be palpable
at the second left interspace. The first sound is accentuated
and the second narrowly or paradoxically split with large
left
to right shunts.

28. Chest X-ray in an adolescent with a large patent ductus
arteriosus. Note the enlargement of the aorta with a prominent aortic
knuckle, large main pulmonary artery-left pulmonary artery and
increased vasculature. There is no X-ray evidence of cardiac
enlargement

29. Differential Diagnosis
The differential diagnosis of PDA includes conditions
capable of giving a continuous murmur over the
precordium.
In addition, combination of a pansystolic murmur with an
ear 1 y diastolic murmur, which are partly superimposed
on
each other, may simulate a continuous murmur over the
precordium. Differential diagnosis of a continuous murmur
includes: (i) coronary arteriovenous fistula; (ii) ruptured
sinus of Valsalva f i stulae into the right side, (iii)
aortopulmonary window; (iv) systemic arteriovenous
fistula
over the chest; (v) bronchial collateral murmurs

30. CONT…
(vi)
pulmonary arteriovenous fistula; (vii) peripheral pulmonic
stenosis; (viii) venous hum including that associated with
total anomalous pulmonary venous connection; and (ix)
small atrial septal defect associated with mitral stenosis
(Lutembacher syndrome). The impression of continuous
murmur due to a combination of a pansystolic murmur
and
regurgitant diastolic murmur occurs most commonly in
VSD
associated with aortic regurgitation.

31. Treatment
A large PDA is better tolerated by term newborns when
compared to premature newborns. Premature newborns
with hemodynamically significant PDA that results in
heart failure, respiratory distress or necrotizing
enterocolitis require prompt management. Indomethacin
or ibuprofen is likely to be effective before the age of 2-
weeks in preterm newborns and is unlikely to be useful
in term babies.

32. The dose of indomethacin is 0.2 mg/kg/
dose, orally, every 12-24 hr for three doses (second and
third doses are at 0.1 mg/kg/dose for <48 hr-old and
0.25 mg/kg/ dose for >7-days-old). Hepatic or renal
insufficiency and bleeding tendency are contraindications.
Newborns not responding to these agents require surgical
ligation. The PDA in term infants may close spontaneously
as late as one month after birth and it is worth waiting if
the duct is large unless the heart failure is refractory

33. The dose of indomethacin is 0.2 mg/kg/
dose, orally, every 12-24 hr for three doses (second and
third doses are at 0.1 mg/kg/dose for <48 hr-old and
0.25 mg/kg/ dose for >7-days-old). Hepatic or renal
insufficiency and bleeding tendency are contraindications.
Newborns not responding to these agents require surgical
ligation. The PDA in term infants may close spontaneously
as late as one month after birth and it is worth waiting if
the duct is large unless the heart failure is refractory.

34. CY ANOTIC HEART DISEASE
Tetralogy of Fallot
Among cyanotic CHO, tetralogy of Fallot (TOF) has a
relatively favorable natural history that allows survival
beyond infancy in about 75% of cases. As a result it is the
most common cyanotic CHO encountered beyond the age
of 1-yr constituting almost 75% of all blue patients. The
physiology is that of VSO with pulmonic stenosis,
Anatomically it is characterized by the
classic tetrad: severe right ventricle outflow obstruction,
large VSO, aorta that overrides the VSO and right
ventricular hypertrophy. Multiple anatomical variations
of TOF exist, which have a bearing on treatment

35. Clinical Features
Patients with TOF may become symptomatic any time
after birth. Neonates as well as infants may develop anoxic
spells (paroxysmal attacks of dyspnea). Cyanosis may be
present from birth or make its appearance some years after
birth. The commonest symptoms are dyspnea on exertion
and exercise intolerance. The patients assume a sitting
posture-squatting-as soon as they get dyspneic.
Although squatting is not specific for TOF, it is the
commonest congenital lesion in which squatting is noted.

36. Anoxic spells occur predominantly after waking up or
following exertion. The child starts crying, becomes
dyspneic, bluer than before and may lose consciousness.
Convulsions may occur. The frequency varies from once
in a few days to numerous attacks every day.
Physical examination discloses cyanosis, clubbing,
slightly prominent 'a' waves in the jugular venous pulse,
normal sized heart with a mild parasternal impulse, a
systolic thrill in less than 30% patients, normal first sound,
single second sound and an ejection systolic murmur
which ends before the audible single second sound. The
electrocardiogram in TOF shows right axis
deviation with right ventricular hypertrophy

37. The murmur shortens and the cyanosis increases with
increasing severity of the right ventricular outflow
tract
obstruction. Paroxysmal attacks of dyspnea can be
present
with mild as well as severe TOF. However, effort
intolerance is directly related to the severity.

38. Diagnosis
The diagnosis of TOF is confirmed by
echocardiography;
cardiac catheterization is seldom necessary. Additional
specific information required for surgical decision is
also
obtained through echocardiography. Cardiac
catheterization
or CT /MRI may be required in older children with
limited
echo windows.

39. Course and Complications
Patients with TOF are subject to many difficulties. The
pulmonic stenosis becomes progressively severe with age.
The dyspnea and increasing exercise intolerance limit
patient activities. Each attack of paroxysmal dyspnea or
anoxic spell is potentially fatal. Anemia, by decreasing the
oxygen carrying capacity of blood, reduces the exercise
tolerance still further. It can result in cardiac enlargement
and congestive cardiac failure making diagnosis difficult.
Patients are prone to infective endocarditis.

40. Chest X-ray in Tetralogy of Fallot with right aortic arch.
The key findings are reduced lung vasculature as suggested by the
dark lung fields, normal heart size, concavity in the region of the main
pulmonary artery(pulmonary bay). This X-ray also shows a right aortic
arch. The arrow indicates the indentation of the right arch on the
right side of the trachea

41. Neurological complications occur frequently. Anoxic infarction
in the central nervous system may occur during an anoxic
spell and result in hemiplegia. Paradoxicnl e111bolis111 to
central nervous system and venous thrombosis due to
sluggish circulation from polycythemia can also result in
hemiplegia. Brain abscess is not an infrequent complication.
It should be suspected in any cyanotic patient presenting
with irritability, headache, convulsions, vomiting with or
without fever and neurological deficit. The fund us need
expert evaluation since polycythemia results in congested
retina and recognition of papilledema is difficult.

42. Treatment
The medical management of TOF is limited to prevention
and management of complications and correction of
anemia. Oral beta-blockers help prevent cyanotic spells.
Maximally tolerated doses of propranolol ranging from
0.5-1.5 mg/kg/ dose should be administered. Iron
supplementation
is recommended for all infants and young
children with TOF. Definitive surgery for TOF involves closure
of the VSD
and relief of the RVOT obstruction. Often the relief of the
RVOT obstruction involves the placement of a transannular
patch across the pulmonary valve and valvectomy
resulting in severe pulmonary regurgitation.

43. Tricuspid Atresia
Congenital absence of the tricuspid valve is called
tricuspid
Atresia. The right ventricle is hypoplastic.
The inflow portion is absent. The hemodynamics is
described above; see single ventricle physiology.

44. Clinical Features Clinical presentation depends on the
state of pulmonary
flow that may be diminished or increased. Clinically,
patients
who have diminished pulmonary blood flow
constitute 90% and symptoms and physical signs are more
or less identical to TOF. Features suggesting tricuspid
atresia are (i) left ventricular type of apical impulse; (ii)
prominent large a waves in jugular venous pulse; (iii)
enlarged liver with presystolic pulsations (a waves and
(iv) the electrocardiogram which is characterized by left
axis deviation and left ventricular hypertrophy. T

45. Course
Patients with tricuspid atresia follow a course similar
to TOF.
They are cyanosed at birth. Anoxic spells and squatting
may
be present; patients are relatively sicker than TOF.
Treatment
Tricuspid atresia is categorized as 'single ventricle
physiology' and management is on similar lines.

46. Ebstein Anomaly
An unusual and rare cyanotic congenital heart disease
with diminished pulmonary blood flow results from an
abnormality of the tricuspid valve. The posterior as
well
as the septal leaflet of the tricuspid valve is displaced
downwards to a variable extent.

47. Hemodynamics
The tricuspid valve anomaly results in obstruction to
forward flow of blood as well as regurgitation of blood
from the right ventricle into the right atrium. In addition,
there is a large part of the right ventricle that is atrialized
as a result of downward displacement of the tricuspid
valve attachment. The foramen ovale may be patent or
there is an
atrial septal defect allowing a right to left shunt to occur.
This results in cyanosis. The greater the tricuspid valve
displacement, the more the cyanosis.

48. Clinical Features
Patients present with history of cyanosis, effort intolerance
and fatigue. They may also give history suggestive of
paroxysmal attacks of tachycardia. Cyanosis varies from
slight to severe; clubbing is present. The jugular venous
pulse may show a dominant 'V' wave but there is usually
no venous engorgement. The precordium is quiet with a
left ventricular apical impulse. A systolic thrill may be
palpable at the left sternal border. The first sound is split,
however, the tricuspid component cannot be made out,
resulting in a single, normally audible first sound.

49. The X-ray shows cardiac enlargement
due to right atrial and right ventricular enlargement.
The
main pulmonary artery segment may be prominent
and
the aortic knuckle small The pulmonary
vasculature is diminished. Two dimension
echocardiogram
is diagnostic as it outlines the displaced tricuspid
valve (

50. Chest X-ray in Ebstein anomaly. There is considerable
enlargement of the right atrium. The lung vascularity is reduced

51. Transpositoi n of Great Vessels
Transposition of great vessels (TGA) is defined as aorta
arising from the right ventricle and pulmonary artery from the
left ventricle. By definition, therefore, the great vessels
(aorta and the pulmonary artery) arise from inappropriate
ventricles, both of which must be present and identifiable.
In TGA the aorta generally lies anterior and to the right of
the pulmonary artery. Since the systemic and pulmonary
circulations are separate, survival depends on the presence
of atrial, ventricular or aortopulmonary communications.
TGA is classified into (a) with intact ventricular septum,
and (b) with VSD. The latter group is further subdivided
into cases with and without pulmonic stenosis. Patients
with complete TGA, VSD and pulmonic stenosis are
included in tetralogy physiology.

52. The pulmonary
artery saturation is thus always higher than the
aortic saturation. Survival depends on the mixing available
The pulmonary
artery saturation is thus always higher than the
aortic saturation. Survival depends on the mixing available.
The neonates become symptomatic due to
severe hypoxemia and systemic acidosis soon after birth.
Presence of a VSD of adequate size results in good
mixing. As the fetal pulmonary vasculature regresses, the
pulmonary blood flow increases and results in congestive
failure around 4-10 weeks of age.

53. The failing left ventricle
as well as the large pulmonary blood flow increase the
left atrial pressure. The patients, therefore, have
pulmonary venous hypertension as well. The mixing with
a large VSD can be so good that at times cyanosis can be
missed. The presence of a large VSD equalizes pressures
in the two ventricles as well as the great arteries. The
pulmonary artery also carries a large flow. Patients with
TGA and a large VSD develop pulmonary vascular
obstructive disease (Eisenmenger physiology) early in life

54. Egg on side appearance in transposition. This characteristic
appearance is seen only in about one-third cases and results from a
narrow pedicle of the heart because of malpostion of great vessels

55. Physical findings consist of
cyanosis, cardiomegaly, congestive failure, normal first
sound, single or normally split second sound and grade
II-IV ejection systolic murmur. Apical third sound gallop
or a mid-diastolic rumble may be present.
Electrocardiogram
shows right axis deviation with biventricular, right
ventricular or left ventricular hypertrophy. Chest X-ray
shows cardiomegaly, plethoric lung fields and features of
pulmonary venous hypertension.

56. Treatment Prostagladin El can help reduce cyanosis in
selected cases
by keeping the PDA open. Interim palliation can be
accomplished through a balloon atrial septostomy.
This procedure can be accomplished in
catheterization
laboratory or in the ICU under echocardiographic
guidance. Septostomy is successful only up to the
age of 6-12 weeks and gives temporary relief by
providing
better mixing and reducing left atrial pressure.

57. The arterial switch operation is now established as the
treatment of choice for TGA and most centers endeavor
to offer this procedure for all infants with TGA. In this
operation, the pulmonary artery and aorta are transected.
The distal aorta is anastomosed to the proximal pulmonary
stump (neo-aortic root) and the pulmonary artery to the
proximal aortic stump (neopulmonary artery). The
coronary arteries are moved along to the neo-aortic root
along with a cuff of aortic tissue to allow suturing without
compromise of coronary blood flow.

58. Corrected TGA
In corrected TGA the right atium is connected to the
left
ventricle and vice-versa. The left ventricle gives rise to
the pulmonary artery and right ventricle to the aorta.
The
aorta lies anterior and to the left of the pulmonary
artery
(hence the term L-TGA). The ascending aorta forms
the
left upper border of the cardiac silhouette.

59. Here, all the pulmonary veins instead of joining the left
atrium are connected anomalously to result in the total
pulmonary venous blood reaching the right atrium. The
anatomical classification of TAPVC is into supracardiac,
cardiac, infracardiac and mixed varieties. In the
supracardiac TAPVC the pulmonary veins join together
to form a common pulmonary vein that may drain into
the left innominate vein or the right superior vena cava.
In the cardiac TAPVC the veins join the coronary sinus or
enter the right atrium directly. In the infracardiac variety
the common pulmonary vein drains into the portal vein.

60. Hemodynamics
TAPVC results in the pulmonary venous blood reaching
the right atrium, which also receives the systemic venous
blood. This results in almost complete mixing of the two
venous returns. The blood flow to the left atrium is the
right to left shunt through a patient foramen ovale or atrial
septal defect. The oxygen saturation of the blood in the
pulmonary artery is often identical to that in the aorta
because of mixing of the blood in the right atrium.
Physiologically TAPVC can be divided into (a) patients
with pulmonary venous obstruction, and (b) patients
without pulmonary venous obstruction.

61. Clinical Picture
TAPVC of the non-obstructive type is commoner than the
obstructive type. Patients present with cyanosis and
congestive failure as the fetal pulmonary vasculature
regresses. The onset of congestive failure is around four
to ten weeks of age. Occasionally, with large pulmonary
blood flow, the cyanosis may be minimal or clinically not
recognizable. The patients are irritable and have failure
to thrive. Besides features of congestive failure the patients
have cardiomegaly, hyperkinetic precordium normal or
accentuated first sound, widely split and fixed second
sound with accentuated pulmonic component, a grade two
to four pulmonary ejection systolic murmur and a
tricuspid flow murmur.

62. The electrocardiogram in TAPVC with or without
pulmonary venous obstruction shows right axis
deviation
and right ventricular hypertrophy. Chest
roentgenogram
shows cardiomegaly with plethoric lung fields in
nonobstructive
TAPVC.

63. Chest X-ray from a newborn with obstructed infracardiac
total anomalous pulmonary venous connection. Note the characteristic
ground glass appearanceA

64. Management
Operation is indicated as early as possible since 80% of
infants die within the first 3 months of life without surgical
help. Obstructed TAPVC needs surgery at short notice.
The results of surgery for both forms of TAPVC are good
in most modern centers but newborns and infants with
obstructed T APVC need a long time to recover after
surgery. These patients are prone to develop pulmonary
hypertensive crisis in the postoperative period. A small
proportion of infants develop progressive pulmonary
venous obstruction after repair of T APVC that is often not
easy to correct.

65. Cyanosis and High Pulmonary Flow
Apart from transposition of great vessels and total
anomalous pulmonary venous connection, single ventricle
without obstruction to pulmonary blood flow, persistent
truncus arteriosus, tricuspid atresia with absence of
obstruction to pulmonary blood flow and double outlet
right ventricle without pulmonic stenosis present with
cyanosis and increased pulmonary blood flow. Clinically
patients present with congestive failure in the neonatal
period and are characterized by cyanosis, cardiomegaly
and failure to thrive.

66. Almost 80% die within 3 months of
life due to congestive cardiac failure or pulmonary
infection. Those who survive develop pulmonary arterial
hypertension due to pulmonary vascular obstructive
disease. Echocardiography is necessary to arrive at the
specific diagnosis. Since the mortality of unoperated
patients is high and patients develop Eisenmenger
syndrome early in life, it is necessary that patients
presenting with cyanosis and increased pulmonary blood
flow be referred to specialized centers as early as possible.

67. Pulmonary Arterial H ypertension
Patients with Eisenmenger syndrome have severe
pulmonary arterial hypertension resulting in a right to
left
shunt at the atrial, ventricular or pulmonary arterial
level.
Eisenmenger co mplex consists of pulmonary arterial
hypertension with a VSD providing the right to left
shunt.

68. Hemodynamics
The pulmonary arterial hypertension is due to pulmonary
vascular obstructive disease. If a communication is present
at the pulmonary arterial level or the ventricular level,
the right ventricular pressure cannot go beyond the
systemic pressure. The right to left shunt decompresses
the right ventricle. The right ventricle has only concentric
hypertrophy without significant increase in the size. In
patients who have a PDA or VSD, there is only a mild
parasternal impulse without significant heave. In patients
who do not have a VSD or PDA, the right ventricle besides
hypertrophy also dilates.

69. The right to left shunt at the atrial
level is an indication of right ventricular failure to
accommodate this volume and push into the
pulmonary
artery. Patients of Eisenmenger syndrome with
communication
at the atrial level only, exhibit a parastemal heave
and cardiac enlargement. The right ventricular
pressure
may even be higher than the systemic pressure.

70. A right to left shunt at the atrial level or the ventricular
level reaches the ascending aorta and is thus
distributed
to the whole systemic circulation. This results in equal
cyanosis of fingers and toes. A right to left shunt
through
a PDA is directed downwards into the descending
aorta,
which results in differential cyanosis affecting lower
limbs,
with pink upper limbs.

71. Clinical Features
Patients present with history of cyanosis, fatigue, effort
intolerance and dyspnea. There may also be history of
repeated chest infections in childhood. On physical
examination they have cyanosis and clubbing. Differential
cyanosis separates patients who have a PDA from those
who have a VSD or atrial septal defect. The features
indicative of pulmonary arterial hypertension consist of
parasternal impulse and palpable second sound.

72. Treatment
Ideally pulmonary vascular obstructive disease should be
prevented. This means early diagnosis and correction of
all CHD associated with increased pulmonary blood flow.
Patients with cyanosis and increased pulmonary blood
flow develop Eisenmenger physiology very early and need
to be operated by 2-3 months of age. Medications
are available for the management of pulmonary
hypertension
(see later section on pulmonary hypertension).

73. Chest X-ray in Eisenmenger syndrome following ventricular
septal defect. The proximal right pulmonary artery is enlarged. There
is a relative paucity of vasculature in the periphery with a sudden
tapering of caliber of the right pulmonary artery (pruning)

74. OBSTRUCTIVE LESIONS
Aortic Stenosis
Pathologically the site of obstruction may be at valve level,
above the valve (supravalvar) or below the valve
(subvalvar). At the valve level the aortic stenosis results
from either an unicuspid or a bicuspid aortic valve. Rarely
the aortic valve annulus may itself be small. Supravalvar
aortic stenosis results from obstruction in root of aorta,
above the aortic valve, as in Williams syndrome.
Subvalvar
aortic stenosis may be discrete (membranous),
fibromuscular or muscular (hypertrophic obstructive
cardiomyopathy).

75. Hemodynamics
Valvar obstruction is overcome by raising the systolic
pressure of the left ventricle. This is brought about by
concentric hypertrophy of the left ventricle. Because of a
powerful, muscular left ventricle, the emptying of the left
ventricle is complete but the duration of the systole is
prolonged. The prolongation of left ventricular ejection
time causes delayed closure of the aortic valve resulting
in delayed A2. The flow across the obstruction results in
the aortic ejection systolic murmur that is typically
diamond shaped, starting after the first sound and ending
before the aortic component of the second sound with a
mid-systolic peak. The systolic murmur is always palpable
as a thrill at the second right interspace, suprasternal notch
and the carotid vessels.

76. Clinical Features
Patients with mild to moderate AS are asymptomatic. With
severe stenosis, the initial symptom is generally dyspnea
on exertion. The patients may also give history of angina
on effort and syncope. Presence of any one of these three
symptoms suggests severe AS. The blood pressure is
normal with mild disease; the width of pulse pressure
relates inversely with severity of AS resulting in low
amplitude prolonged duration pulse. The cardiac size
remains normal unless left ventricular failure is present

77. The apical impulse is forcible or heaving. In severe AS
the fourth sound may be palpable. If left ventricular failure
is present the third sound may be palpable. A systolic thrill
is palpable at the second right interspace, suprasternal
notch and the carotid arteries. The first sound is normal
and followed by an ejection click in valvar aortic stenosis.
The aortic component of the second sound (A2) is delayed
but not diminished in intensity in AS.

78. The electrocardiogram reveals left ventricular
hypertrophy. Presence of ST and T wave changes suggest
severe disease. It should be remembered that
a normal electrocardiogram does not exclude severe
aortic
stenosis. The chest X-ray shows a normal sized heart with
dilated ascending aorta in valvar AS. In supravalvar and
subvalvar stenosis the thoracic roentgenogram may be
normal. Presence of cardiac enlargement indicates severe
AS. Echocardiogram can not only identify the site of
stenosis, but using Doppler assess the gradient across the
obstruction fairly accurately.

79. Treatment
Patients with AS should be followed closely, with 6-12
monthly electrocardiogram. Symptoms should be carefully
evaluated. Doppler echo can be used to quantitate
the gradient at each visit and ventricular function should
be monitored. Severe AS is risk for sudden death. Patients
should be discouraged from outdoor games, athletics,
competitive sports and strenuous exercises if AS is
significant (gradient of 50 mm Hg or more).

80. Balloon aortic valvuloplasty is the procedure of choice
for valvar AS. A balloon introduced through the femoral
artery can be placed at the aortic valve and inflated to
tear the valve along the commissure. It is indicated if the
gradient is above 75 mm Hg. Supravalvar and subvalvar
AS do not respond to balloon dilation; the procedure
should also be avoided in patients with significant aortic
regurgitation. Surgical options include aortic valve repair
and replacement with a prosthetic valve. Patients need to
be administered anticoagulants if they have a prosthetic
valve replacement and careful followup to prevent/ detect
complications, such as restenosis, thrombus or pannus
formation and infective endocarditis.

81. Coarctation of the Aorta
Coarctation of the aorta is located at the junction of the
arch with the descending aorta. It is a sharp indentation
involving the anterior, lateral and posterior wall of the
aorta; the medial wall is spared. It may be distal or
proximal to the ductus or ligamentum arteriosus and also
the left subclavian artery. Forty to 80% patients have a
bicuspid aortic valve

82. Hemodynamics
In fetal life, the right ventricular output passes down the
descending aorta through a wide ductus arteriosus. The left
ventricular output empties into the innominate, left carotid
and left subclavian arteries and little output reaches the
descending aorta. The portion of the aorta distal to the left
subclavian and before the portion where the ductus
arteriosus joins is called the isthmus. At birth, the isthmus
is the narrowest part of the aorta. Following closure of the
ductus arteriosus, the descending aorta must receive its
total supply from the left ventricle via the ascending aorta.
Neonates with severe coarctation therefore become
symptomatic
immediately as the duct starts to close. However,
a significant proportion present late.

83. Clinical Features
Coarctation has a continuum of severity and the age at
presentation is linked to severity. Newborns with severe
coarctation presents as soon as the duct start to close. Infants with
coarctation
occasionally present with left ventricular dysfunction and
heart failure. It is important to examine femoral pulses in
newborns and infants with heart failure. Later in life,
coarctation is often not associated with symptoms.
The only symptoms in uncomplicated coarctation may
be intermittent claudication, pain and weakness of legs
and dyspnea on running. Examination shows delayed and
weak femorals compared to strong brachial arteries. The
heart size remains normal with a left ventricular forcible
or heaving apex.

84. A systolic thrill may be palpable in the
suprasternal notch. There are prominent arterial
pulsations
in the suprasternal notch and the carotid vessels.
The first sound is accentuated and sometimes followed
by a constant ejection click.

85. The electrocardiogram shows left ventricular
hypertrophy;
ST and T wave changes below the age of 15 yr
suggests additional aortic stenosis or endocardial
fibroelastosis.
Chest X-ray shows a normal sized heart with
prominent ascending aorta and the aortic knuckle. In
an
overpenetrated film, the site of coarctation can be well
localized as the proximal segment is dilated and there
is
post stenotic dilatation of the distal segment.

86. Course and Compllcatlons
Coarctation may result in congestive failure in infancy. If
congestive failure does not occur in infancy, it is unlikely
to occur throughout the pediatric age group unless
complicated
by infective endocarditis or anemia. The complications
of coarctation include rupture of berry intracranial
aneurysm and dissection of aorta. These
complications are rare in children. Infective endarteritis
may in occur the wall of aorta distal to coarctation or there
could be endocarditis involving the bicuspid aortic valve

87. Treatment
Relief of coarctation is recommended as soon as diagnosis
is made when coarctation is severe. In newborns and
infants surgery is preferred. In older children, adolescents
and adults, balloon dilation is often undertaken. The
recurrence rates of balloon dilation in newborns is over
90% and this procedure should only be done as interim
palliation in the face of heart failure and severe ventricular
dysfunction. Prostaglandin El is used to maintain ductal
patency prior to surgery in the first few weeks of life.

88. Pulmonic Stenosis (Pure Pulmonic Stenosis or
Pulmonic Stenosis with Intact Ventricular
Septum)
Pulmonic stenosis (PS) is usually valvar or subvalvar
(iniundibular PS). Uncommonly pulmonic stenosis
may
be in the pulmonary artery above the valve or in the
main
right or left branches or the peripheral branches.

89. Hemodynamics and Clinical Features
Flow across the narrow pulmonary valve results in a
pulmonary ejection systolic murmur and a thrill in the
left
second interspace. To keep the flow normal the right
ventricle increases its systolic pressure and develops
concentric right ventricular hypertrophy. The
pulmonary
artery beyond the obstruction shows poststenotic
dilatation visible on the thoracic roentgenogram as a
dilated pulmonary arterial segment.

90. Treatment
Val var PS generally does not increase in severity with time
unless it is severe or diagnosed in the newborn period.
Patients with mild PS (gradients of 50 mm Hg or less) need
annual review. Balloon pulmonary valvuloplasty is the
treatment of choice for isolated valvar PS. The procedure
is sometimes technically challenging in newborn with
critical PS. Surgical treatment is indicated only if balloon
valvotomy is unsuccessful, as in patients with dysplastic
valves or small pulmonary valve annulus. lnfundibular
PS requires surgical resection